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54 lines
1.2 KiB
54 lines
1.2 KiB
// Copyright 2016 The Prometheus Authors |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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// +build darwin dragonfly freebsd linux netbsd openbsd |
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package flock |
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import ( |
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"os" |
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"syscall" |
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) |
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type unixLock struct { |
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f *os.File |
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} |
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func (l *unixLock) Release() error { |
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if err := l.set(false); err != nil { |
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return err |
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} |
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return l.f.Close() |
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} |
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func (l *unixLock) set(lock bool) error { |
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how := syscall.LOCK_UN |
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if lock { |
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how = syscall.LOCK_EX |
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} |
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return syscall.Flock(int(l.f.Fd()), how|syscall.LOCK_NB) |
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} |
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func newLock(fileName string) (Releaser, error) { |
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f, err := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE, 0644) |
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if err != nil { |
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return nil, err |
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} |
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l := &unixLock{f} |
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err = l.set(true) |
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if err != nil { |
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f.Close() |
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return nil, err |
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} |
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return l, nil |
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}
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